Chapter III: Part 3

_History._--In 791 Charlemagne drove the Avars from the territory between the Ens and the Raab, and united it to his empire under the name of _the Eastern Mark_ (that is, March or boundary land); and from the establishment by him of a margraviate in this new province the former Austrian Empire took its rise. On the invasion of Germany by the Hungarians it became subject to them from 900 till 955, when Otho I, by the victory of Augsburg, reunited a great part of this province to the German Empire, which by 1043 had extended its limits to the Leitha. The margraviate of Austria was hereditary in the family of the Counts of Babenberg (Bamberg) from 982 till 1156, in which year the boundaries of Austria were extended so as to include the territory above the Ens, and the whole was created a duchy. The territory was still further increased in 1192 by the gift of the duchy of Styria as a fief from the Emperor Henry VI, Vienna being by this time the capital. The male line of the House of Bamberg became extinct in 1246, and the Emperor Frederick II declared Austria and Styria a vacant fief, the hereditary property of the German emperors. In 1282 the Emperor Rudolph granted Austria, Styria, and Carinthia to his two sons, Albert and Rudolph. The former became sole ruler (duke), and since then, until 12th Nov., 1918, Austria remained under the House of Habsburg. Albert, who was an energetic ruler, was elected emperor in 1298, but was assassinated in 1308. The first of his successors whom we need specially mention was Albert V, son-in-law of the Emperor Sigismund. He assisted Sigismund in the Hussite wars, and was elected, after his death, King of Hungary and of Bohemia, and German emperor (1438). Ladislaus, his posthumous son, was the last of the Austrian line proper, and its possessions devolved upon the collateral Styrian line in 1457; since which time the House of Austria furnished an unbroken succession of German emperors.

In 1453 the Emperor Frederick III, a member of this House, had conferred upon the country the rank of an archduchy before he himself became ruler of all Austria. His son Maximilian I, by his marriage with Mary, the surviving daughter of Charles the Bold, united the Netherlands to the Austrian dominions. After the death of his father, in 1493, Maximilian was made Emperor of Germany, and transferred to his son Philip the government of the Netherlands. He also added to his paternal inheritance Tyrol, with several other territories, particularly some belonging to Bavaria, and acquired for his family new claims to Hungary and Bohemia. The marriage of his son Philip to Joanna of Spain raised the House of Habsburg to the throne of Spain. Philip, however, died in 1506, and the death of Maximilian, in 1519, was followed by the union of Spain and Austria, his grandson (the eldest son of Philip), Charles I, King of Spain, being elected Emperor of Germany as Charles V. Charles thus became the greatest monarch in Europe, but in 1521 he ceded to his brother Ferdinand all his dominions in Germany. Ferdinand I, by his marriage with Anna, the sister of Louis II, King of Hungary, acquired the kingdoms of Hungary and Bohemia, with Moravia, Silesia, and Lusatia, the appendages of Bohemia. To oppose him the woywode of Transylvania, John Zapolya, sought the help of the Sultan, Soliman II, who appeared in 1529 at the gates of Vienna, but was compelled to retreat. In 1535 a treaty was made by which John Zapolya was allowed to retain the royal title and half of Hungary, but after his death new disputes arose, and Ferdinand maintained the possession of Lower Hungary only by paying Soliman the sum of 30,000 ducats annually (1562). In 1556 Ferdinand obtained the imperial crown, when his brother Charles laid by the sceptre for a cowl. He died in 1564, leaving his territories to be divided amongst his three sons.

Maximilian II, the eldest, succeeded his father as emperor, obtaining Austria, Hungary, and Bohemia; Ferdinand, the second son, received Tyrol and Lower Austria; and Charles, the youngest, obtained Styria, Carinthia, Carniola, and Goerz. Maximilian died in 1576, and was succeeded on the imperial throne by his eldest son Rudolph II, who had already been crowned King of Hungary in 1572, and King of Bohemia in 1575. Rudolph's reign was distinguished by the war against Turkey and Transylvania; the persecutions of the Protestants, who were driven from his dominions; the cession of Hungary in 1608; and in 1611 of Bohemia and his hereditary estates in Austria to his brother Matthias. Matthias, who succeeded Maximilian on the imperial throne, concluded a peace with the Turks, but was disturbed by the Protestant Bohemians, who took up arms in defence of their religious rights, thus commencing the Thirty Years' War. After his death in 1619 the Bohemians refused to acknowledge his successor, Ferdinand II, until after the battle of Prague in 1620, when Bohemia had to submit, and was deprived of the right of choosing her king. Lutheranism was strictly forbidden in all the Austrian dominions. Hungary, which revolted under Bethlem Gabor, Prince of Transylvania, was, after a long struggle, subdued. During the reign of Ferdinand III (1637-57), successor of Ferdinand II, Austria was continually the theatre of war; Lusatia was ceded to Saxony in 1635; and Alsace to France in 1648, when peace was restored in Germany by the Treaty of Westphalia.

The Emperor Leopold I, son and successor of Ferdinand III, was victorious through the talents of Prince Eugene in two wars with Turkey; and Vienna was delivered by Sobieski and the Germans from the attacks of Kara Mustapha in 1683. In 1687 he united Hungary to Transylvania, and in 1699 restored to Hungary the country lying between the Danube and the Theiss. It was the chief aim of Leopold to secure to Charles, his second son, the inheritance of the Spanish monarchy, and in 1701, upon the victory of French diplomacy in the appointment of the grandson of Louis XIV, the War of the Spanish Succession commenced. Leopold died in 1705, but Joseph I, his eldest son, continued the war. As he died without children in 1711, his brother Charles was elected emperor, but was obliged to accede in 1714 to the Peace of Utrecht, by which Austria received the Netherlands, Milan, Mantua, Naples, and Sardinia. In 1720 Sicily was given to Austria in exchange for Sardinia. This monarchy now embraced over 190,000 sq. miles; but its power was weakened by new wars with Spain and France. In the peace concluded at Vienna (1735 and 1738) Charles VI was forced to cede Naples and Sicily to Spain and part of Milan to the King of Sardinia; and in 1739, by the Peace of Belgrade, he was obliged to transfer to the Porte Belgrade, Serbia, &c., partly in order to secure the succession to his daughter, Maria Theresa, by the Pragmatic Sanction. He died in 1740.

On Maria Theresa's marriage to Francis Stephen, Duke of Lorraine (the dynasty henceforth being that of Habsburg-Lorraine), and her accession to the Austrian throne, the Empire was threatened with dismemberment. Frederick II of Prussia subdued Silesia; the Elector of Bavaria was crowned in Lintz and Prague, and in 1742 chosen emperor under the name of Charles VII; Hungary alone supported the heroic and beautiful queen. Charles, however, died in 1745, and the husband of Theresa was crowned Emperor of Germany as Francis I; but a treaty concluded in 1745 confirmed to Frederick the possession of Silesia, and by the Peace of Aix-la-Chapelle, 1748, Austria was obliged to cede the duchies of Parma, Piacenza, and Guastalla to Philip, Infant of Spain, and several districts of Milan and Sardinia. To recover Silesia, Maria Theresa formed an alliance with France, Russia, Saxony, and Sweden, and entered upon the Seven Years' War; but by the Peace of Hubertsberg, 1763, Silesia was recognized as Prussian territory. On the death of Francis I, in 1765, Joseph II, his eldest son, was appointed to assist his mother in the government and elected Emperor of Germany. The partition of Poland (1772) gave Galicia and Lodomeria to Austria, which also obtained Bukowina from the Porte in 1777. At the death of the Empress in 1780 Austria contained 235,000 sq. miles, with a pop. estimated at 24,000,000.

The liberal home administration of the Empress was continued and extended by her successor, Joseph II, who did much to further the spread of religious tolerance, education, and the industrial arts. The Low Countries, however, revolted, and he was unsuccessful in the war of 1788 against the Porte. His death took place in 1790. He was succeeded by his eldest brother, Leopold II, under whom peace was restored in the Netherlands, and in Hungary, and also with the Porte. On the death of his sister and her husband Louis XVI of France he formed an alliance with Prussia, but died in 1792, before the French revolutionary war broke out.

His son, Francis II, succeeded, and was elected German Emperor, by which time France had declared war against him as King of Hungary and Bohemia. In 1795, in the third partition of Poland, West Galicia fell to Austria, and by the Peace of Campo-Formio (1797) she received the largest part of the Venetian territory as compensation for her loss of Lombardy and the Netherlands. In 1799 Francis, in alliance with Russia, renewed the war with France until 1801, when the Peace of Luneville was concluded. In 1804 Francis declared himself hereditary Emperor of Austria as Francis I, and united all his States under the name of the Empire of Austria, immediately taking up arms once more with his allies Russia and Great Britain against France. The war of 1805 was terminated by the Peace of Pressburg (26th Dec.), by which Francis had to cede to France the remaining provinces of Italy, as well as to give up portions of territory to Bavaria, Wuertemberg, and Baden, receiving in return Salzburg and Berchtesgaden. After the formation of the Confederation of the Rhine (12th July, 1806) Francis was forced to resign his dignity as Emperor of Germany, which had been in his family more than 500 years. A new war with France in 1809 cost the monarchy 42,380 sq. miles of territory and 3,500,000 subjects. Napoleon married Maria Louisa, daughter of the Emperor, and in 1812 concluded an alliance with him against Russia. But in 1813 Francis again declared war against France, and formed an alliance with Britain, Prussia, and Sweden against his son-in-law. By the Congress of Vienna (1815) Austria gained Lombardy and Venetia, and recovered, together with Dalmatia, the hereditary territories which it had been obliged to cede.

In the troubled period following the French revolution of 1830 insurrections took place in Modena, Parma, and the Papal States (1831-2), but were suppressed without much difficulty; and though professedly neutral during the Polish insurrections Austria clearly showed herself on the side of Russia, with whom her relations became more intimate as those between Great Britain and France grew more cordial. The death of Francis I (1835) and accession of his son, Ferdinand I, made little change in the Austrian system of government, and much discontent was the consequence. In 1846 the failure of the Polish insurrection led to the incorporation of Cracow with Austria. In Italy the declarations of Pio Nono in favour of reform increased the difficulties of Austria, and in Hungary the opposition under Kossuth and others assumed the form of a great constitutional movement. In 1848, when the expulsion of Louis Philippe shook all Europe, Metternich found it impossible any longer to guide the helm of the State, and the Government was compelled to admit a free press and the right of citizens to arms. Apart from the popular attitude in Italy and in Hungary, where the Diet declared itself permanent under the presidency of Kossuth, the insurrection made equal progress in Vienna itself, and the royal family, no longer in safety, removed to Innsbruck. After various ministerial changes the Emperor abdicated in favour of his nephew, Francis Joseph; more vigorous measures were adopted; and Austria, aided by Russia, reduced Hungary to submission.

The year 1855 is memorable for the Concordat with the Pope, which put the educational and ecclesiastical affairs of the Empire entirely into the hands of the Papal see. In 1859 the hostile intentions of France and Sardinia against the possessions of Austria in Italy became so evident that she declared war by sending an army across the Ticino; but after disastrous defeats at Magenta and Solferino she was compelled to cede Milan and the north-west portion of Lombardy to Sardinia. In 1864 she joined with the German States in the war against Denmark, but a dispute about Schleswig-Holstein involved her in a war with her allies (1866), while at the same time Italy renewed her attempts for the recovery of Venice. The Italians were defeated at Custozza and driven back across the Mincio; but the Prussians, victorious at Koeniggraetz (or Sadowa), threatened Vienna. Peace was concluded with Prussia on 23rd Aug. and with Italy on 3rd Oct., the result of the war being the cession of Venetia through France to Italy and the withdrawal of Austria from all interference in the affairs of Germany.

For nearly half a century (from 1866 to 1914) the internal affairs of Austria-Hungary gave much occupation to statesmen of the dual monarchy. Hungarian demands for self-government were finally agreed to, and the Empire was divided into the two parts already mentioned--Austria and Hungary. This settlement was consummated by the coronation of the Emperor Francis Joseph I, at Budapest, as King of Hungary, on 8th June, 1867. In the same year the Concordat of 1855 came up for discussion, and measures were passed for the re-establishment of civil marriage, the emancipation of schools from the domination of the Church, and the placing of different creeds on a footing of equality. The fact of the Austro-Hungarian dominions comprising so many different nationalities gave the central Government much trouble, both in regard to internal and to external affairs. In regard to the 'Eastern Question', for instance, the action of Austria was hampered by the sympathies shown by the Magyars for their blood relations, the Turks, while the Slavs were naturally more favourable to Russia. During the war between Russia and Turkey in 1877-8 Austria remained neutral; but at its close it was decided at the Congress of Berlin that Bosnia and Herzegovina should in future be administered by Austria instead of Turkey. In 1908, taking advantage of the condition of Turkey, Austria formally annexed these provinces. By the middle of Oct., 1918, the Austro-Hungarian monarchy began to break up into independent national States. Four States of some size laid claim to independence, viz. German-Austria, Czecho-Slovakia (recognized by the Allies), Hungary, and Yugo-Slavia. On 13th Oct., 1921, German Austria signed with Hungary the Burgenland pact, agreeing to a plebiscite in several districts. For recent history of Austria, see _Francis Joseph; European War._--Cf. S. Whitman, _Austria_ (in Story of the Nations Series); H. W. Steed, _The Hapsburg Monarchy._

AUTEUIL ([=o]-t[.e]-y[.e]), formerly a suburban village of Paris, but now enclosed within the fortifications.

AUTOBIOG'RAPHY, a department of literature of which, as a definite branch or form at least, we have no very ancient examples, though many autobiographical details are contained, for instance, in Cicero's and Pliny's letters, while St. Augustine has left a fragmentary autobiography in his _Confessions_. Various writers of note, without claiming or perhaps intending to write a formal autobiography, have left similar materials in the form of their own memoirs or reminiscences, or, for a portion of their lives, in diaries. The chief English diarists are Pepys and Evelyn, while Crabb Robinson is an admirable modern example. Brief autobiographies were written by Gibbon, Hume, and Sir Walter Scott (of his early life only), and among other writers who have given us autobiographies or kindred works are Fanny Burney, Cobbett, Haydon, Miss Mitford, Harriet Martineau, Leigh Hunt, Hugh Miller (in _My Schools and Schoolmasters_), John Stuart Mill, Anthony Trollope, Sir Henry Taylor, Miss F. P. Cobbe, Carlyle, Ruskin, Herbert Spencer, Alexander Bain, and Alfred Russel Wallace. Lord Roberts's _Forty-one Years in India_ and General Grant's _Personal Memoirs_ are most interesting autobiographical works by men of action. One of the most famous of autobiographies is that of the Italian Benvenuto Cellini. See _Biography_.

AUTOCHROME. See _Photography_.

AUTOCHTHONES ([a:]-tok'tho-n[=e]z), the Greek name for the aboriginal inhabitants of a country. See _Aborigines_.

AU'TOCLAVE (derived from the Gr. _autos_, self, and Lat. _clavis_, key) is a strong steam-tight vessel in which hydrolysis of liquids can be carried out, under pressure, at temperatures considerably higher than their normal boiling-points. The vessels may be of copper, iron, or other suitable material, are sometimes enamelled within, or may have renewable refractory linings when used for corrosive liquids. Some types have mechanical agitators. Used in the manufacture of candles, coal-tar colours, &c. May be heated by high-pressure steam or in baths of oil or molten lead. See _Papin_.

AU'TOCRAT (Gr. _autos_, self, _kratos_, rule), an absolute or uncontrolled ruler; the head of a State who is not controlled by any constitutional limitations, such as the Tsars of Russia till 1917.

AUTO-DE-FE (Sp.); AUTO-DA-FE (Pg.), literally, 'act of faith'. See _Inquisition_.

AU'TOGRAPH, a person's own handwriting; an original manuscript or signature, as opposed to a copy. The practice of collecting autographs or signatures originated in Germany and the Low Countries, chiefly among members of the universities, and dates at least from the sixteenth century. Among the earliest collections known are those of John Cotton and Hans Sloane in the British Museum, and of Philippe de Bethune, brother of Sully, and Lomenie de Brienne at the Bibliotheque Nationale. The most celebrated collection formed in England in recent years is that of Alfred Morrison.

AUTOMATIC WRITING. See _Psychical Research_; _Spiritualism_.

AUTOM'ATISM, the confinement of activity in men or animals within a purely mechanical limit, resulting from injury to or partial removal of the brain.

AUTOM'ATON (Gr. _automatos_, spontaneous), a self-moving machine performing actions like those of a living being, and often shaped like one. The walking statues of Daedalus, the flying dove of Archytas, the brazen head of Friar Bacon, the iron fly of Regiomontanus, the door-opening figure of Albertus Magnus, the parading knights of the clock presented to Charlemagne by Harun al Rashid, the toy carriage and attendants constructed by Camus for Louis XIV, the flute-player, tambour-player, and duck of Vaucanson, and the writing child of the brothers Droz are among the more noteworthy of traditional automata. See _Conjuring_.

AUTOMOBILE. See _Motor Vehicles_.

AUTON'OMY, the power of a State, institution, &c., to legislate for itself.

AUTOPH'AGI (-j[=i]), birds which feed themselves as soon as hatched.

AU'TOPLASTY, the operation by which wounds and diseased parts are repaired with healthy tissues taken from other parts of the same person's body.

AUTOPLATE. See _Printing_.

AUTOP'SY, literally, personal observation or inspection, commonly restricted to post-mortem examination. See _Coroner_.

AU'TOTYPE, a species of photographic print. A thin sheet of gelatine on paper is rendered sensitive to light by treatment with bichromate of potash, and then exposed under an ordinary photographic negative. The portions of gelatine affected by the light become insoluble, the remainder of the gelatine is then washed away, and the picture remains reproduced in the gelatine, there being slight elevations and depressions corresponding with the distribution of light and shade. This may be printed from, but it is more often made use of to obtain electrotypes or other reverses, from which impressions can more easily be taken.

AUTUMN, the season between summer and winter, in the northern hemisphere often regarded as embracing August, September, and October, or three months about that time. The beginning of the astronomical autumn is 22nd Sept., the autumnal equinox; and the end is 21st Dec., the shortest day. The autumn of the southern hemisphere takes place at the time of the northern spring.

AUTUN ([=o]-t[.u]n; ancient, BIBRACTE, later, AUGUSTODUNUM), a town, South-Eastern France, department of Saone-et-Loire. It has two Roman gates of exquisite workmanship, the ruins of an amphitheatre and of several temples, the cathedral of St. Lazare, a fine Gothic structure of the twelfth century with chapels added in the fifteenth; manufactures of carpets, woollens, cotton, velvet, hosiery, &c. Pop. 15,498.

AUTUNITE, a hydrous phosphate of uranium and calcium, crystallizing in the rhombic system in yellow plates. Like other minerals of the uranium series it shows radio-activity.

AUVERGNE ([=o]-v[=a]r-ny[.e]), a province, Central France, now merged into departments Cantal and Puy-de-Dome, and an arrondissement of Haute-Loire. The Auvergne Mountains, separating the basins of the Allier, Cher, and Creuse from those of the Lot and Dordogne, contain the highest points of Central France: Mount Dor, 6188 feet; Cantal, 6093 feet, and Puy-de-Dome, 4806 feet. The number of extinct volcanoes and general geologic formation make the district one of great scientific interest. The minerals include iron, copper, and lead, and there are warm and cold mineral springs. Auvergne contributes a large supply to the labour markets of Paris and Belgium, there being in Paris alone some 50,000 Auvergnats.

AUXERRE ([=o]-s[=a]r), a town, France, department of Yonne, 110 miles S.E. of Paris. Principal edifices: a fine Gothic cathedral, unfinished; the abbey of St. Germain, with curious crypts; and an old episcopal palace, now the Hotel de Prefecture; it manufactures woollens, hats, casks, leather, earthenware, violin strings, &c.; trade, chiefly in wood and wines, of which the best known is white Chablis. Pop. 21,930.

AUXOM'ETER, an instrument to measure the magnifying powers of an optical apparatus.

AUXONNE ([=o]-son; ancient, AUSSONA), a town, France, department of Cote-d'Or (Burgundy), on the Saone; a fortified place, with some manufactures. Pop. 6300.

A'VA, a town in Asia, formerly the capital of Burma, on the Irawadi, now almost wholly in ruins.

AVA-AVA, ARVA, KAVA, or YAVA (_Macropiper methysticum_), a plant of the nat. ord. Piperaceae (pepper family), so called by the inhabitants of Polynesia, who make an intoxicating drink out of it. Its leaves are chewed with betel, in South-Eastern Asia.

AVAD'AVAT. See _Amadavat_.

AV'ALANCHES, large masses of snow or ice precipitated from the mountains, and distinguished as _wind_ or _dust avalanches_ when they consist of fresh-fallen snow whirled like a dust-storm into the valleys; as _sliding avalanches_ when they consist of great masses of snow sliding down a slope by their own weight; and as _glacier_ or _summer avalanches_ when ice-masses are detached by heat from the high glaciers.

AVAL ISLANDS. Same as _Bahrein Islands_.

AVALLON ([.a]-v[.a]-l[=o]n), a town of Central France, department Yonne. Pop. 5900.

AV'ALON, a sort of fairyland or elysium mentioned in connection with the legends of King Arthur, being his abode after disappearing from the haunts of men: called also _Avilion_. The name is also identified with Glastonbury; and has been given to a peninsula of Newfoundland.

AVAN'TURINE, or AVEN'TURINE, a variety of quartz containing glittering spangles of mica through it; also a sort of artificial gem of similar appearance.

AV'ARS, a nation, probably of Turanian origin, who at an early period may have migrated from the region east of the Tobol in Siberia to that about the Don, the Caspian Sea, and the Volga. A part advanced to the Danube in A.D. 555, and settled in Dacia. They served in Justinian's army, aided the Lombards in destroying the kingdom of the Gepidae, and in the sixth century conquered under their Khan Bajan the region of Pannonia. They then won Dalmatia, pressed into Thuringia and Italy against the Franks and Lombards, and subdued the Slavs dwelling on the Danube, as well as the Bulgarians on the Black Sea. But they were ultimately limited to Pannonia, where they were overcome by Charlemagne, and nearly extirpated by the Slavs of Moravia. After 827 they disappear from history. Traces of their fortified settlements are found, and known as Avarian rings. See _Lesghians_.

AVATAR', more properly AVATARA, in Hindu mythology, an incarnation of the Deity. Of the innumerable avatars the chief are the ten incarnations of Vishnu, who appeared successively as a fish, a tortoise, a boar, a man-lion, a dwarf, &c.

AVATCH'A, a volcano and bay in Kamchatka. The volcano, which is 9000 feet high, was last active in 1855. The town of Petropavlovsk lies in the bay.

AVEBURY ([=a]v'be-ri), a village of England, in Wiltshire, occupying the site of a so-called Druidical temple, which originally consisted of a large outer circle of 100 stones, from 15 to 17 feet in height, and about 40 feet in circumference, surrounded by a broad ditch and lofty rampart, and enclosing two smaller circles. Few traces now remain of the structure. On the neighbouring downs are numerous barrows or tumuli, one of which, called Silbury Hill, rises to the height of 130 feet, with a circumference of 2027 feet at the base, covering fully 5 acres.

AVEBURY, John Lubbock, first Baron. See _Lubbock_.

AVEIRO ([.a]-v[=a]'i-r[u:]), a coast town in Portugal, province of Douro, with a cathedral, an active fishery, and a thriving trade. Pop. 11,523.

AVELLINO ([.a]-vel-l[=e]'n[=o]), a town in Southern Italy, capital of the province of Avellino, 29 miles east of Naples, the seat of a bishop. Avellino nuts were celebrated under the Romans. Pop. 24,620. Area of the province, 1165 sq. miles; pop. 411,813.

A'VE MARI'A ('Hail, Mary'), the first two words of the angel Gabriel's salutation (_Luke_, i, 28), and the beginning of the very common Latin prayer to the Virgin in the Roman Catholic Church. Its lay use was sanctioned at the end of the twelfth century, and a papal edict of 1326 ordains the repetition of the prayer thrice each morning, noon, and evening, the hour being indicated by sound of bells called the Ave Maria or Angelus Domini. The prayers are counted upon the small beads of the rosary, as the pater-nosters are upon the large ones.

AVE'NA. See _Oat_.

AV'ENS, the English name of two rosaceous plants of the genus Geum. Common avens, or herb-bennet, _G. urb[=a]num_, possesses astringent properties, and was formerly used in medicine. The mountain avens, _Dryas octopetala_, belongs to the same nat. ord.

AV'ENTAILE, the movable face-guard of the helmet, through which the wearer breathed.

AV'ENTINE, one of the seven hills of Rome, east of the Tiber. It was included in the city by Servius Tullius.

AVEN'TURINE. See _Avanturine_.

AV'ERAGE, in maritime law, any charge or expense over and above the freight of goods, and payable by their owner.--_General average_ is the sum falling to be paid by the owners of ship, cargo, and freight, in proportion to their several interests, to make good any loss or expense intentionally incurred for the general safety of ship and cargo, e.g. throwing goods overboard, cutting away masts, port dues in cases of distress, &c.--_Particular average_ is the sum falling to be paid for unavoidable loss when the general safety is not in question, and therefore chargeable on the individual owner of the property lost. A policy of insurance generally covers both general and particular average, unless specially excepted.--_Averaging_, in Stock Exchange language, denotes the operation of a speculator in increasing transactions at a higher or lower price when the price is moving against him, so that the average price of the whole will be higher or lower than his original purchase or sale.

AVER'NUS, a lake, now called LAGO D'AVERNO, in Campania, Italy, between the ancient Cumae and Puteoli, about 8 miles from Naples. It is the crater of an old volcano, and is in some places 180 feet deep. Formerly the gloom of its forest surroundings and its mephitic exhalations caused it to be regarded as the entrance to the infernal regions. It was the fabled abode of the Cimmerians, and especially dedicated to Proserpine.

AVERROES (a-ver'o-es; corrupted from IBN ROSHD), the most renowned Arabian philosopher, born at Cordova, in Spain, 1126, died at Morocco 1198. His ability procured him the succession to his father's office of chief magistrate, and the King of Morocco appointed him at the same time cadi in the province of Mauretania. Accused of being an infidel, he was, however, deprived of his offices, and banished to Spain; but, being persecuted there also, he fled to Fez, where he was condemned to recant and undergo public penance. Upon this he went back to his own country, where the Caliph Almansur finally restored him to his dignities. Averroes regarded Aristotle as the greatest of all philosophers, and devoted himself so largely to the exposition of his works as to be called among the Arabians _The Interpreter_. He wrote a compendium of medicine, and treatises on theology, philosophy, jurisprudence, &c. His commentaries upon Aristotle appeared before 1250 in a Latin translation attributed to Michael Scott, the reputed wizard (1194-1250), and others. Averroes was at once a philosopher, a theologian, and a theosophist.

AVERRUNCA'TOR, a garden implement for pruning trees without a ladder, consisting of two blades similar to stout shears, one fixed rigidly to a long handle, and the other moved by a lever to which a cord passing over a pulley is attached.

AVER'SA, a well-built town of Southern Italy, 7 miles N. of Naples, in a beautiful vine and orange district, the seat of a bishop, with a cathedral and various religious institutions, and a large lunatic asylum. Andreas of Hungary, husband of Queen Joanna I, was strangled in a convent here, 18th Sept., 1345. Pop. 23,203.

AVESNES ([.a]-v[=a]n), a town of France, department Nord. Pop. 5829.

AVESTA. See _Zendavesta_.

AVEYRON ([.a]-v[=a]-r[=o][n.]), a department occupying the southern extremity of the central plateau of France, traversed by mountains belonging to the Cevennes and the Cantal ranges; principal rivers: Aveyron, Lot, and Tarn, the Lot alone being navigable. The climate is cold, and agriculture is in a backward state, but considerable attention is paid to sheep-breeding. It is noted for its 'Roquefort cheese'. It has coal, iron, and copper mines, besides other minerals. Area, 3385 sq. miles; capital, Rhodez. Pop. (1921), 332,940.

AVEZZANO ([.a]-vet-zae'n[=o]), a town of S. Italy, province Aquila. Pop. 11,279.

AV'IARY, a building or enclosure for keeping, breeding, and rearing birds. Aviaries appear to have been used by the Persians, Greeks, and Romans, and are highly prized in China. In England they were in use at least as early as 1577, when William Harrison refers to "our costlie and curious aviaries". An aviary may be simply a kind of very large cage, or a series of enclosures.

AVIATIK, a German type of biplane. It was originally built at Mulhausen in Alsace.

AVIATION. See _Aeronautics_.

AVICEN'NA, or EBN-SINA, an Arabian philosopher and physician, born at Kharmaithen, in the province of Bokhara, A.D. 980. After practising as a physician he quitted Bokhara at the age of twenty-two, and for a number of years led a wandering life, settling at last at Hamadan, subsequently as vizier of the Emir. On the death of his patron he lived in retirement at Hamadan, but having secretly offered his services to the Sultan of Ispahan he was imprisoned by the new Emir. Escaping, he fled to Ispahan, was received with great honour by the Sultan, and passed there in quietness the last fourteen years of his life, writing upon medicine, logic, metaphysics, astronomy, and geometry. His philosophy was Aristotelianism mingled with neo-Platonism, and his influence is most marked in Dante and the Mystics. He died at Hamadan, in Northern Persia, 1037, leaving many writings, mostly commentaries on Aristotle. Of his 100 treatises the best known is the _Canon Medicinae_, which was still in use as a textbook at Louvain and Montpellier in the middle of the seventeenth century. His _Philosophia Orientalis_, mentioned by Roger Bacon, is lost.

AVIE'NUS, Rufus Festus, a Latin descriptive poet, who flourished about the end of the fourth century A.D., and wrote _Descriptio Orbis Terrae_, a general description of the earth; _Ora Maritima_, an account of the Mediterranean coasts, &c.

AVIFAU'NA, a collective term for the birds of any region.

AVIGLIANO ([.a]-v[=e]l-yae'n[=o]), a town of S. Italy, province Potenza. Pop. 17,413.

AVIGNON ([.a]-v[=e]-ny[=o]n; ancient, AVENIO), an old town of S.E. France, capital of department Vaucluse, on the left bank of the Rhone; enclosed by lofty battlemented and turreted walls, well built, but with rather narrow streets. It is an archbishop's see since 1475, and has a large and ancient cathedral on a rock overlooking the town, the immense palace in which the Popes resided (used as a barracks and prison for a long time), and other old buildings. The industries of the city are numerous and varied, the principal being connected with silk. The silk manufacture and the breeding of silk-worms are the principal employments in the district. Here Petrarch lived several years, and made the acquaintance of Laura, whose tomb is in the Franciscan church. From 1309 to 1377 seven Popes in succession, from Clement V to Gregory XI, resided in this city. After its purchase by Pope Clement VI, in 1348, Avignon and its district continued, with a few interruptions, under the rule of a vice-legate of the Pope's till 1791, when it was formally united to the French Republic. Pop. 49,304.

AVIGNON BERRIES. See _French Berries_.

AVILA (ae'v[=e]-l[.a]), a town of Spain, capital of province of Avila, a modern division of Old Castile. It is the see of the Bishop suffragan of Santiago, with fine cathedral. Once one of the richest towns of Spain. Principal employment in the town, spinning; in the province, breeding sheep and cattle. Pop., town, 12,060; province, 214,008.

AVILA, Gil Gonzalez d', a Spanish antiquary and biographer, 1577-1658; made historiographer of Castile in 1612, and of the Indies in 1641. Most valuable works: _Teatro de las Grandezas de Madrid_, 1623, and _Teatro Ecclesiastico_, 1645-53.

AVILA Y ZUNIGA (ae'v[=e]-l[.a] [=e] thoe-ny[=e]'g[.a]), Don Luis d', Spanish general, diplomatist, and historian; a favourite of Charles V; born about 1490, died about 1560. His chief work, printed in 1548 and translated into five languages, was on the war of Charles V in Germany.

AVILES ([.a]-v[=e]'les), a town of Northern Spain, province Oviedo, with a good harbour. Pop. 13,660.

AVIZ, an order of knighthood in Portugal, instituted by Sancho, its first king, and having as its original object the subjection of the Moors.

AVIZAN'DUM, in Scots law, private consideration. To make _avizandum_ is to remove a cause from the public court to the private consideration of the judge.

AVLO'NA (Ital. _Valona_), a seaport of Albania on the Adriatic, with a considerable trade. It was occupied and made a naval and military base by the Italians during the European War. Pop. 6500.

AVO'CA, or OVOCA, a river and valley in Ireland, County Wicklow, celebrated as the scene and subject of one of Moore's _Irish Melodies_. The river is formed by the union of the Avonbeg and Avonmore, and below the junction receives the Aughrim, the name in Celtic signifying 'the meeting of the waters'. After a course of about 9 miles it falls into the sea about a mile below Arklow. The scenery here is singularly beautiful, and attracts many visitors.

AVOCA'DO-PEAR. See _Alligator-pear_.

AVOGAD'RO'S LAW, in physics, asserts that equal volumes of different gases at the same pressure and temperature contain an equal number of molecules.

AVOIRDUPOIS (a-v[.e]r'd[u:]-pois; from old French, literally, 'goods of weight'), a system of weights used for all goods except precious metals, gems, and medicines, and in which a pound contains 16 ounces, or 7000 grains, while a pound troy contains 12 ounces, or 5760 grains. A hundredweight contains 112 pounds avoirdupois; a _cental_ of 100 pounds is common in America, and is a legal British weight. See _Weights and Measures_.

AV'OLA, a seaport on the east of Sicily, with a trade in almonds, sugar, &c. Pop. 17,711.

A'VON, the name of several rivers in England, of which the principal are: 1. The Upper Avon, rising in Leicestershire, and flowing S.W. into the Severn at Tewkesbury. Stratford-on-Avon lies on this river. 2. The Lower Avon, rising in Gloucestershire, and falling into the Severn N.W. of Bristol; navigable as far as Bath. 3. In Monmouthshire. 4. In Wiltshire and Hampshire, entering the English Channel at Christchurch Bay. There are also streams of this name in Wales and Scotland.

AVONMOUTH, a place at the mouth of the River Avon, 6 miles from Bristol, and connected with it by rail and river, with large docks belonging to the Bristol corporation, and forming part of the shipping accommodation of that city.

AV'OSET, a bird about the size of a lapwing, of the genus Recurvirostra (_R. avosetta_), family Scolopacidae (snipes), ord. Grallatores. The bill is long, slender, elastic, and bent upward toward the tip, the legs long, the feet webbed, and the plumage variegated with black and white. The bird feeds on worms and other small animals, which it scoops up from the mud of the marshes and fens that it frequents. It is found in Europe, Asia, Africa, and America; but the American species is slightly different from the others.

AVRANCHES ([.a]-vrae[n.]sh; ancient, ABRINCAE), a town, France, department La Manche, about 3 miles from the Atlantic. It formerly had a fine cathedral, destroyed during the first French revolution. Manufactures: lace, thread, and candles. Pop. 7174.

AWE ([a:]), a Scottish loch in Argyllshire, about 28 miles long and 2 broad, and communicating by the Awe with Loch Etive. Ben Cruachan stands at its northern extremity. It has many islands and beautiful scenery, and abounds in trout, salmon, &c.

AXE, or AX, a well-known tool for cutting or chipping wood, consisting of an iron head with an arched cutting edge of steel, which is in line with the wooden handle of the tool, and not at right angles to it as in the adze.

AXEL. See _Absalon_.

AXE-STONE. See _Jade_.

AXHOLME ISLE (aks'[=o]m), a sort of island in England formed by the Rivers Trent, Idle, and Don, in the north-west angle of Lincolnshire, 17 miles long, 4-1/2 broad.

AXIL, or AXILLA, in botany, the angle between the upper side of a leaf and the stem or branch from which it springs. Buds usually appear in the axils, and flowers or flower-stalks growing in this way are called _axillary_.

AX'IM, a town of W. Africa, on the Gold Coast.

AX'INITE, a mineral, silicate of alumina, lime, &c., with boracic acid, deriving its name from the form of the crystals, the edges of which bear some resemblance to the edge of an axe.

AXIN'OMANCY, an ancient method of divination by the movements of an axe (Gr. _axin[=e]_) balanced on a stake, or of an agate placed on a red-hot axe. The names of suspected persons being uttered, the movements at a particular name indicated the criminal.

AX'IOM, a universal proposition, which the understanding must perceive to be true as soon as it perceives the meaning of the words, and therefore called a _self-evident truth_: e.g. _A_ is _A_. In mathematics, axioms are those propositions which are assumed without proof, as being in themselves independent of proof, and which are made the basis of all the subsequent reasoning; as, 'The whole is greater than its part'; 'Things that are equal to the same thing are equal to one another'. See _Geometry_.

AXIS, the straight line, real or imaginary, passing through a body or magnitude, on which it revolves, or may be supposed to revolve; especially a straight line with regard to which the different parts of a magnitude, or several magnitudes, are symmetrically arranged; e.g. the _axis of the world_, the imaginary line drawn through its two poles.

In _botany_ the word is also used, the stem being termed the _ascending axis_, the root the _descending axis_.

In _anatomy_ the name is given to the second vertebra from the head, that on which the _atlas_ moves. See _Atlas_.

AXIS (_Cervus axis_), a species of Indian deer, also known as the Spotted Hog-deer, of a rich fawn colour, nearly black along the back, with white spots, and under parts white. Breeds freely in many parks in Europe.

AX'MINSTER, a market town, England, county Devon, on the Axe, at one time celebrated for its woollen cloth and carpet manufactures, and giving name to an expensive variety of carpet having a thick soft pile, and also to a cheaper variety. Pop. (1921), 2049.

AX'OLOTL (_Amblyst[)o]ma macul[=a]tum_), a curious Mexican amphibian, not unlike a newt, from 8 to 10 inches in length, with gills formed of three long ramified or branch-like processes floating on each side of the neck. It reproduces by laying eggs, and was for some time regarded as a perfect animal with permanent gills. It is said, however, that they frequently lose their gills like the other members of the genus, though some authorities maintain that the true axolotl never loses its gills, and that merely confusion with _A. tigr[=i]num_ has led to the belief, as this species sometimes retains its branchiae, though usually it loses them. The axolotl is esteemed a luxury by the Mexicans. There are a number of species of Amblystoma in North America.

AX'UM, or AKSUM, a town in Tigre, a division of Abyssinia, once the capital of an important kingdom, and at one time the great depot of the ivory trade in the Red Sea. It is the seat of an _abuna_ or Patriarch, and has a pop. of 5000. The site of the town still exhibits many remains of its former greatness.

AYACUCHO (ae-y[.a]-koe'ch[=o]), the name of a department of Peru, and of its capital. The department has an area of 18,185 sq. miles; a pop. of 302,469. The town (formerly Guamanga or Huamanga) has a cathedral and a university, and a pop. of 20,000.

AYALA ([.a]-yae'l[.a]), Pedro Lopez de, Spanish historian and poet, Chancellor of Castile in the second half of the fourteenth century, and the author of a history of Castile from 1350 to 1396. He took an active part in the struggle between Henry II and Pedro the Cruel, and was taken prisoner by the English in 1367. During his English captivity he wrote part of his chief poetical work, _A Book in Rhyme concerning Court Life_. Died 1407.

AYAMONTE ([.a]-y[.a]-mon't[=a]), a seaport town, Spain, province of Huelva, 2 miles from the mouth of the Guadiana. Pop. 6000.

AYASS'OLUK. See _Ephesus_.

mys madagascariensis_)]

AYE-AYE ([=i]-[=i]; _Cheir[)o]mys madagascariensis_), an animal of Madagascar, so called from its cry; now referred to the lemur family. It is about the size of a hare, has large flat ears and a bushy tail; large eyes; long sprawling fingers, the third so slender as to appear shrivelled; colour, musk-brown, mixed with black and grey ash; feeds on grubs, fruits, &c.; habits, nocturnal. See _Primates_, _Lemurs_.

AYESHA (a-yesh'a), daughter of Abu-Bekr and favourite wife of Mahomet, though she bore him no child, born in 610 or 611. After his death she opposed the succession of Ali, but was defeated and taken prisoner. She died at Medina in 677 or 678 (A.H. 58).

AYLESBURY ([=a]lz'be-ri), county town of Buckinghamshire, England, with a fine old parish church; chief industries, silk-throwing, printing, making condensed milk, and poultry-rearing for the London market. The Aylesbury duck, also called 'white English', is famous. Previous to 1885 it and its hundred sent two members to Parliament, and it still gives its name to a parliamentary division. Pop. (1921), 12,114.

AY'LOFFE, Sir Joseph, an English antiquary, born about 1708, died 1781; member of the first council of the Society of Antiquaries, a commissioner for the preservation of State papers, the author and editor of several works, of which the best known is his _Calendars of the Auntient Charters_, &c.

AYMARAS ([=i]'m[.a]-r[.a]z), an Indian race of Bolivia and Peru, speaking a language akin to the Quichua.

AY'MON, the surname of four brothers, Alard, Richard, Guiscard, and Renaud, who hold a first place among the heroes of the Charlemagne cycle of romance. Their exploits were the subject of a romance, _Les Quatre Fils d'Aymon_, by Huon de Villeneuve, a trouvere of the thirteenth century, and Renaud is a leading figure in Ariosto's _Orlando_.

AYR ([=a]r), a town of Scotland, a royal and parliamentary burgh, and capital of Ayrshire, at the mouth of the River Ayr, on the Firth of Clyde. It was the site of a Roman station. William the Lion built a castle there in 1197 and constituted it a royal burgh in 1202; and the Parliament which confirmed Robert Bruce's title to the crown sat in Ayr. It is picturesquely situated, and has excellent public and other buildings. Two bridges connect Ayr proper with the suburbs of Newton and Wallacetown, a third stands farther up the river. The 'New Brig' of Burns's 'Brigs of Ayr' (built in 1788) had to be replaced by a new structure in 1879, while the 'Auld Brig' (built in 1252) still stands, after being repaired. Carpets, lace goods, leather, iron goods, &c., are manufactured. The harbour accommodation is good, and in particular coals are largely exported. The house in which Burns was born stands within 1-1/2 miles of the town, and near 'Alloway's auld haunted kirk', and a monument to him is near. Ayr unites with Ardrossan, Irvine, Prestwick, Saltcoats, and Troon in sending a member to Parliament. Pop. 32,986.--The county has an area of 724,523 acres. It is divided into the districts of Carrick in the south, Kyle in the middle, and Cunningham in the north. The surface is irregular, and a large portion of it hilly, but much of it is fertile. The principal streams are the Ayr, Stinchar, Girvan, Doon, Irvine, and Garnock. Coal and iron are abundant; and there are numerous collieries and ironworks. Limestone and freestone are also abundant. Agriculture is in a flourishing state, the principal crops being oats, turnips, and early potatoes, while dairy husbandry is extensively practised; the Ayrshire cows, referred to in the eighteenth century as the Cunningham, are celebrated as milkers, and Ayrshire cheese ('Dunlop' and 'Cheddar') has a high reputation. Woollen manufactures are extensive, particularly carpets and bonnets; lace goods are largely made; Kilmarnock is a centre of engineering and of dairying education. Goods made include explosives, boots and shoes, chemicals, and leather. Chief towns, Ayr, Kilmarnock, Irvine, Ardrossan, Saltcoats, Stevenston, Maybole. Ayr and Buteshire send three members to Parliament. Pop. 267,600 (1918).

AYRER ([=i]'rer), Jacob, a German dramatist of the sixteenth century, who almost rivalled Hans Sachs in copiousness and importance. He was a citizen and legal official of Nuremberg, and died in 1605. His works, published at Nuremberg in 1618, under the title _Opus Theatricum_, include thirty comedies and tragedies and thirty-six humorous pieces.

AYRTON, William Edward, English physicist and electrical engineer, born in 1847. From 1873 to 1879 he was professor of natural philosophy and telegraphy in the Imperial College of Engineering at Tokio. In 1879 he was appointed professor of applied physics in the City and Guilds of London Institute. He invented an ammeter, voltmeter, &c., in conjunction with Professor Perry. He died in 1908. He published _Practical Electricity_, and many papers on scientific subjects.

AYTOUN ([=a]'tun), Sir Robert, poet, born in Fifeshire, Scotland, 1570, died 1638. After studying at St. Andrews he lived for some time in France, whence, in 1603, he addressed a panegyric in Latin verse to King James on his accession to the crown of England. By the grateful monarch he was appointed one of the gentlemen of the bedchamber, and private secretary to the queen, receiving also the honour of knighthood. At a later period of his life he was secretary to Henrietta Maria, queen of Charles I. His poems are few in number, but are distinguished by elegance of diction. Several of his Latin poems are preserved in the work called _Delitiae Poetarum Scotorum_, published at Amsterdam in 1637 at the expense of Sir John Scot of Scotstarvet.

AYTOUN, William Edmonstoune, poet and prose writer, born at Edinburgh in 1813, died at Blackhills, Elgin, 1865. He studied at the University of Edinburgh, became a writer to the signet in 1835, and passed as advocate in 1840. He issued a volume of poems in 1832, by 1836 was a contributor to _Blackwood's Magazine_, and in 1840 he published the _Life and Times of Richard 1_. In 1848 he published a collection of ballads entitled _Lays of the Scottish Cavaliers_, which has proved the most popular of all his works. It was followed in 1854 by _Firmilian, a Spasmodic Tragedy_ (intended to ridicule certain popular writers); the _Bon Gaultier Ballads_ (parodies and other humorous pieces, in conjunction with Theodore Martin), 1855; in 1856 the poem _Bothwell_; and in subsequent years by _Norman Sinclair_, _The Glenmutchkin Railway_, and other stories. In 1858 he edited a critical and annotated collection of the _Ballads of Scotland_. A translation of the poems and ballads of Goethe was executed by him in conjunction with Theodore Martin. In 1845 he became professor of rhetoric and English literature in the University of Edinburgh--a position which he held till his death. In 1852 he was appointed Sheriff of Orkney and Shetland.

AYUNTAMIENTO ([.a]-y[u:]n-t[.a]-m[=e]-en't[=o]), the name given to the town and village councils in Spain and Spanish America.

AYU'THIA, the ancient capital of Siam, on the Menam, now a scene of splendid ruin.

AZA'LEA, a genus of plants, nat. ord. Ericaceae, or heaths, remarkable for the beauty and fragrance of their flowers, and distinguished from the rhododendrons chiefly by the flowers having five stamens instead of ten. Many beautiful rhododendrons with deciduous leaves are known under the name of _azalea_ in gardens. The azaleas are common in North America, and two species of these--_A. visc[=o]sa_ and _A. nudifl[=o]ra_--are well known in Britain. An Asiatic species, _A. pontica_, famous for the stupefying effect which its honey is said to have produced on Xenophon's army (cf. _Anabasis_, book iv, chap. 8), is also common in British gardens and shrubberies; and another, _A. indica_, is a brilliant greenhouse plant.

AZAMGARH, or AZIMGARH, a town of India, United Provinces, capital of district of same name. Pop. 18,835.--The district has an area of 2418 sq. miles; a pop. of 1,530,000.

AZEGLIO ([.a]d-zel'y[=o]), Massimo Taparelli, Marquis d', an Italian 'admirable Crichton', artist, novelist, publicist, statesman, and soldier, born at Turin in 1798, died 1866. After gaining some reputation in Rome as a painter, he married the daughter of Manzoni, and achieved success in literature by his novels _Ettore Fieramosca_ (1833) and _Niccolo dei Lapi_ (1841). These embodied much of the patriotic spirit, and in a short time he devoted himself exclusively to fostering the national sentiment by personal action and by his writings. Many of the reforms of Pius IX were due to him. He commanded a legion in the Italian struggle of 1848, and was severely wounded at Vincenza. Chosen a member of the Sardinian Chamber of Deputies, he was, after the battle of Novara, made president of the cabinet, and in 1859 appointed to the military post of general and commissioner-extraordinary for the Roman States.

AZERBAIJAN ([.a]-zer-b[=i]-jaen'), a province of North-Western Persia; area, 40,000 sq. miles; pop. estimated at 2,000,000. It consists generally of lofty mountain ranges, some of which rise to a height of between 12,000 and 13,000 feet. Principal rivers: the Aras or Araxes, and the Kizil-Uzen, which enter the Caspian; smaller streams discharge themselves within the province into the great salt lake of Urumiyah. Agricultural products: wheat, barley, maize, fruit, cotton, tobacco, and grapes. Horses, cattle, sheep, and camels are reared in considerable numbers. Chief minerals: iron, lead, copper, salt, saltpetre, and marble. Tabriz is the capital; pop. 200,000.

AZERBAIJAN, a new republic proclaimed in 1918, after the Russian revolution. It consists of the former Russian province of Baku on the coast of the Caspian Sea. In 1920 the Bolshevist party overthrew the Government and broke off relations with the Entente. See _Russia_.

AZ'IMUTH of a heavenly body, the arc of the horizon comprehended between the meridian of the observer and a vertical circle passing through the centre of the body. The azimuth and altitude give the exact position of the body with reference to the horizon.

AZINCOURT. See _Agincourt_.

AZO COMPOUNDS, a class of substances which belong to the benzene series and contain carbon, hydrogen, and nitrogen. All azo compounds are highly coloured, and in some cases they are direct cotton dyes. The simplest azo compound is _azobenzene_, the chemical formula of which is C_6H_5--N = N--C_6H_5. It is prepared from nitrobenzene by reducing it with stannous chloride and sodium hydroxide. Azobenzene is a highly-coloured crystalline substance, but it is not a dye; it forms, however, the basis of the dyes known as _azodyes_. The azodyes form one of the largest groups of dyes, and derive their name from the presence of the characteristic chemical group --N = N--, known as the _azo_ group. Azo compounds may become exceedingly complicated in structure. They are divided into mon-azo, di-azo, tri-azo compounds according to the number of azo groups present. The well-known dyes Congo Red and Bismarck Brown are azo compounds of complicated structure. Azo dyes were discovered by Griess in 1856, but as a class did not come on the market until about 1876.

AZOF. See _Azov_.

AZO'IC. See _Pre-Cambrian_.

AZOIMIDE, or HYDRAZOIC ACID, N_3H, is an acid liquid of disagreeable odour, producing headache if inhaled. The acid itself and its salts, with the exception of the alkali salts, are exceedingly explosive and dangerous to handle. Lead hydrazoate, PbN_6, is one of the most stable of these salts. It is a more powerful explosive than mercury fulminate, and has been used instead, in the manufacture of detonators.